1. Field
Embodiments relate to a thin film transistor, a display device including the same, and a method of manufacturing the display device.
2. Description of the Related Art
Display devices, e.g., organic light emitting diode display devices and liquid crystal display devices, may include at least one transistor that may be used as a switching element. Generally, a thin film transistor includes a semiconductor layer, a gate electrode on one end of the semiconductor layer to control current flow through the semiconductor layer, and source and drain electrodes connected with both ends of the semiconductor layer to transfer a predetermined amount of electric current through the semiconductor layer.
The semiconductor layer may be formed of polycrystalline silicon (poly-Si) or amorphous silicon (a-Si). However, the poly-Si has been widely used since it exhibits a higher electron mobility than the a-Si. In this case, the poly-Si may be formed by forming an a-Si layer on a substrate and crystallizing the a-Si layer into a poly-Si layer using a crystallization process, e.g., solid phase crystallization (SPC), rapid thermal annealing (RTA), metal-induced crystallization (MIC), metal-induced lateral crystallization (MILC), excimer laser annealing (ELA), or sequential lateral solidification (SLS).
However, when the a-Si layer is formed on the gate electrode and crystallized into a poly-Si layer using ELA or SLS, the heat source of a laser beam, which is irradiated on the a-Si layer, may cause heat to flow toward the gate electrode. The heat flow may then cause insufficient crystal growth of the a-Si. As a result, the poly-Si semiconductor layer may made include an unstable crystal growth region, which may lead to deteriorated driving characteristics and reliability of the thin film transistor.